The purpose of this grant application is to obtain support for the development of a human interproximal fm-radiotelemetric plaque pH system at the University of Iowa. This system will be used for plaque pH evaluation during various food consumption patterns and for the evaluation of anti-glycolytic oral rinses. The study will be conducted in three phases. The first phase will consist of the in vitro development and testing of an fm-radiotelemetric plaque pH system. Initially, a recently commercially available fm transmitter will be adapted for use with a glass pH microelectrode. Two types of approaches will be taken. The first of these entails an entirely encapsulated version which will be designed to remain in the human volunteers oral cavity at all times. The second approach will allow use of the currently used indwelling wire-telemetric appliance adapted to connect the fm-transmitter when fm-telemetry is desired. The telemetric packages will be evaluated in buffer solutions for reliability, accuracy and average life-time expectancy. Following satisfactory performance, in Phase II the telemetric method will be applied for use in eight human volunteers. Volunteers will be selected using plaque pH screening methods to assume maximum plaque pH responses to fermentable carbohydrates. Each volunteer will carry out eight different test sessions consisting of between 8 and 24 hours of continuous plaque pH measurement. Each session will be designed to evaluate a particular food consumption pattern. Results will be analyzed and used to select food sequences that minimize acidogenic responses. Phase III will be conducted in limited numbers of volunteers to evaluate various anti-glycolytic oral rinses for their effect on long-term (12 hours) plaque pH responses. The development of this fm radiotelemetric method provides a significant improvement in the approach to evaluation of food consumption patterns through the use of human interproximal plaque pH measurement. It will be used to aid in the development of new recommendations and approaches to caries preventions.